Immune response to certain antigens that are otherwise weakly antigenic can be enhanced through the use of vaccine adjuvants. Such adjuvants potentiate the immune response to specific antigens and are therefore the subject of considerable interest and study within the medical community.
Research has permitted development of vaccines possessing antigenic epitopes that were previously impossible to produce. For example, currently available vaccine candidates include synthetic peptides mimicking streptococcal, gonococcal, and malarial antigens. These purified antigens are generally weak antigens, however, that require adjuvants in order to evoke protective immunity. However, conventional vaccine adjuvants possess a number of drawbacks that limit their overall use and effectiveness.
Again, this is fine for vaccines but not other uses.
Substances that stimulate immune cells in vitro exhibit similar immuno-stimulatory effects in vivo. These compounds, such as recombinant cytokines, pathogen products (e.g. toxins, lipids, proteins/peptides, carbohydrates and nucleic acids) and other mammalian-derived immunostimulatory molecules (e.g. heat shock proteins, complement, immune complexes and proteoglycans) all induce a measurable pro-inflammatory response both in vitro and in vivo.
Historically, the classic adjuvants have been Freund's complete or incomplete (i.e., without mycobacteria) adjuvants. Edmund Coley described the potential of Coley's toxin for cancer immuno-therapy. Other materials, such as mineral oil and aluminum hydroxide, have also been used as adjuvants, but they invariably suffer from disadvantages. For example, mineral oil is known to produce tissue irritation and to be potentially oncogenic. Alum, the only approved adjuvant in the United States, also induces granulomas at the inoculation site and furthermore it does not effectively induce cell-mediated immunity. Moreover, many of the adjuvants currently available have limited utility because they contain components, that are not metabolizable in humans. Additionally, most adjuvants are difficult to prepare in that they may require time consuming procedures and the use, in some cases, of elaborate and expensive equipment to formulate a vaccine and adjuvant system.
Immunological adjuvants are described in “Current Status of Immunological Adjuvants”, Ann. Rev. Immunol., 1986, 4, pp. 369-388, and “Recent Advances in Vaccine Adjuvants and Delivery Systems” by Derek T O'Hagan and Nicholas M. Valiente. See also U.S. Pat. Nos. 4,806,352; 5,026,543; and 5,026,546 for disclosures of various vaccine adjuvants appearing in the patent literature.
Compounds are described in issued U.S. Pat. Nos. 4,547,511 and 4,738,971 with the general structure (a):
for the treatment of disorders responsive to agents that enhance cell-mediated immunity. An essential component of the molecule as described in the cited patents is the amide substituent as shown in structure (a). The invention did not contemplate combinations with antigens.
Immunostimulatory oligonucleotides and polynucleotides are described in PCT WO 98/55495 and PCT WO 98/16247. U.S. Patent Application No. 2002/0164341 describes adjuvants including an unmethylated CpG dinucleotide (CpG ODN) and a non-nucleic acid adjuvant. U.S. Patent Application No. 2002/0197269 describes compositions comprising an antigen, an antigenic CpG-ODN and a polycationic polymer.
Additionally, issued U.S. Pat. Nos. 4,689,338, 5,389,640, 5,268,376, 4,929,624, 5,266,575, 5,352,784, 5,494,916, 5,482,936, 5,346,905, 5,395,937, 5,238,944, 5,525,612, W099/29693 and U.S. Ser. No. 09/361,544 disclose compounds of the general structure (b):
for the use as “immune response modifiers.”
There has been an effort to find new immune modulators for use as adjuvants for vaccines and immunotherapies that would overcome the drawbacks and deficiencies of conventional immune modulators. In particular, an adjuvant formulation that elicits potent cell-mediated and humoral immune responses to a wide range of antigens in humans and domestic animals, but lacking the side effects of conventional adjuvants and other immune modulators, would be highly desirable. This need could be met by small molecule immune potentiators (SMIPs) because the small molecule platform provides diverse compounds for the selective manipulation of the immune response, necessary for increasing the therapeutic index immune modulators.
Furthermore, it would be desirable to provide novel compounds with a varied capacity to alter levels and/or profiles of cytokine production in human immune cells. Compounds with structural disparities will often times elicit a desired response through a different mechanism of action, or with greater specificity to a target, such as a dendritic cell, modulating potency and lowering side effects when administered to a patient.
The immunosuppressive effect of cytostatic substances has rendered them useful in the therapy of autoimmune diseases such as multiple sclerosis, psoriasis and certain rheumatic diseases. Even here their beneficial effect has to be weighed against the serious side effects that necessitate too low dosages and/or interruption of the treatment.
It is the object of the present invention to provide a combination of active substances that results in a significantly improved cytostatic or cytotoxic effect as compared to conventional cytostatics given alone, e.g. vincristin, methotrexate, cisplatin etc. Thereby, chemotherapies may be offered that combine increasing efficiency with a large reduction of side effects and therapeutic doses. Thus, the therapeutic efficiency of known cytostatic drugs is increased. Also, certain cell lines that are insensitive to chemotherapeutic treatment may become susceptible to chemotherapy by applying the combination of active substances.
Therapeutics that could serve to augment natural host defenses against viral and bacterial infections, or against tumor induction and progression, with reduced cytotoxicity would be very beneficial. The present invention provides such therapeutic agents, and further provides other related advantages.
All of the aforementioned documents are incorporated by reference as if fully set forth herein.